Ancient yogic lore discusses special abilities, called siddhis, which may be attained through the disciplined practice of meditation. From a modern perspective, tales about siddhis are usually dismissed as superstitious nonsense. But when systematic science is applied, abilities once regarded as impossible, ranging from conscious control of the autonomic nervous system to perception through time, are found to be possible after all. This doesn’t mean that all yogic lore is true, but if we’ve overlooked even a tiny proportion of our remarkable capacities, what does this imply about the full range of human potential? And what does it imply about the way that mainstream science has marginalized or ignored such abilities?